Tetrandrine antagonizes acute megakaryoblastic leukaemia growth by forcing autophagy-mediated differentiation

Tetrandrine induces muscle atrophy involving ROS-mediated inhibition of Akt and FoxO3

Tetrandrine (Tet), a well-known drug of calcium channel blocker, has been broadly applied for anti-inflammatory and anti-fibrogenetic therapy. However, due to the functional diversity of ubiquitous calcium channels, potential side-effects may be expected. Our previous report revealed an inhibitory effect of Tet on myogenesis of skeletal muscle. Here, we found that Tet induced protein degradation resulting in the myofibril atrophy. Upon administration with a relative high dose (40 mg/kg) of Tet for 28 days, the mice displayed significantly reduced muscle mass, strength force, and myosin heavy chain (MyHC) protein levels. The MyHC reduction was further detected in C2C12 myotubes after treating with Tet. Interestingly, the expression of Atrogin-1 and Murf-1, the skeletal muscle specific E3 ligases of protein ubiquitin-proteasome system (UPS), was accordingly up-regulated, and the reduced MyHC was significantly mitigated by MG132, a 26S proteasome inhibitor, indicating a key role of UPS in the protein degradation of muscle cells. Further study showed that Tet induced autophagy also participated in the protein degradation. Mechanistically, Tet treatment caused ROS production in myotubes that in turn targeted on FoxO3/AKT signaling, resulting in the activation of UPS and autophagy processes that were involved in the protein degradation. Our study reveals a potential side-effect of Tet on skeletal muscle atrophy, particularly when the drug dose is relatively high.

Enhanced Antitumor Efficacy of Novel Biomimetic Platelet Membrane-Coated Tetrandrine Nanoparticles in Nonsmall Cell Lung Cancer

Nonsmall cell lung cancer (NSCLC) remains one of the leading causes of cancer-related death worldwide, posing a serious threat to global health. Tetrandrine (Tet) is a small molecule in traditional Chinese medicine with proven primary efficacy against multiple cancers. Although previous studies have demonstrated the potential anticancer effects of Tet on NSCLC, its poor water solubility has limited its further clinical application. Herein, a novel nanoparticle-based drug delivery system, platelet membrane (PLTM)-coated Tet-loaded polycaprolactone-b-poly(ethylene glycol)-b-polycaprolactone nanoparticles (PTeNPs), is proposed to increase the potency of Tet against NSCLC. First, tetrandrine nanoparticles (TeNPs) are created using an emulsion solvent evaporation method, and biomimetic nanoparticles (PTeNPs) are prepared by coating the nanoparticles with PLTMs. When coated with PLTMs, PTeNPs are considerably less phagocytized by macrophages than Tet and TeNPs. In addition, compared with Tet and TeNPs, PTeNPs can significantly inhibit the growth and invasion of NSCLC both in vitro and in vivo. With reliable biosafety, this drug delivery system provides a new method of sustained release and efficient anticancer effects against NSCLC, facilitating the incorporation of Tet in modern nanotechnology.

Preliminary Study on the Effect and Molecular Mechanism of Tetrandrine in Alleviating Pulmonary Inflammation and Fibrosis Induced by Silicon Dioxide

This study aims to explore the molecular mechanism of tetrandrine (Tet) in alleviating pulmonary inflammation and fibrosis induced by silica (SiO2) from the perspective of autophagy. C57BL/6J mice were selected as experimental animals, and SiO2 was exposed by intranasal instillation. Tet was intervened by oral gavage. The mice were euthanized on the 7th and 42nd day of SiO2 exposure, and lung tissues were collected for histopathological, molecular biological, immunological, and transmission electron microscopy analysis. The results showed that SiO2 exposure could lead to significant lung inflammation and fibrosis, while Tet could significantly reduce SiO2 exposure-induced lung inflammation and fibrosis. Molecular mechanism research indicated that, compared with SiO2 expose group, Tet intervention could significantly reduce the expression levels of inflammatory cytokines and fibrosis markers (TNF-α, IL-1β, MCP-1, TGF-β1, HYP, Col-I, and Fn), and regulate the expression of key molecules ATG7, microtubule-associated protein 1 light chain 3B (LC3B), and P62 in the autophagy pathway to improve the blocking of autophagic flux, promote the recovery of autophagic lysosomal system function, and inhibit apoptosis. In summary, Tet can alleviate silica-induced lung inflammation and fibrosis, which may be achieved by regulating the expression of key molecules in the autophagy process and associated apoptotic pathway.

Genetic disruption of mammalian endoplasmic reticulum-associated protein degradation: Human phenotypes and animal and cellular disease models

Endoplasmic reticulum-associated protein degradation (ERAD) is a stringent quality control mechanism through which misfolded, unassembled and some native proteins are targeted for degradation to maintain appropriate cellular and organelle homeostasis. Several in vitro and in vivo ERAD-related studies have provided mechanistic insights into ERAD pathway activation and its consequent events; however, a majority of these have investigated the effect of ERAD substrates and their consequent diseases affecting the degradation process. In this review, we present all reported human single-gene disorders caused by genetic variation in genes that encode ERAD components rather than their substrates. Additionally, after extensive literature survey, we present various genetically manipulated higher cellular and mammalian animal models that lack specific components involved in various stages of the ERAD pathway.

Artesunate, a new antimalarial clinical drug, exhibits potent anti-AML activity by targeting the ROS/Bim and TFRC/Fe2+ pathways

BACKGROUND AND PURPOSE

Artesunate, approved by the Food and Drug Administration in 2020 as a new treatment for severe malaria, also shows anti-tumour activity against acute myeloid leukaemia (AML). However, the underlying molecular mechanism(s) of artesunate-induced apoptosis and differentiation of AML is not clearly elucidated.

EXPERIMENTAL APPROACH

The biological effects of artesunate on AML were explored in vitro, using cells from AML patients and leukaemia cell lines, and in vivo, using female C57BL/6 or nude nu/nu BALB/c mice. Underlying mechanisms in vitro were examined with the Trypan blue dye exclusion assay, western blotting and flow cytometry. Effects of artesunate in C57BL/6 mice intravenously injected with murine AML cells (C1498-GFP) were assessed by numbers of AML cells and by survival.

KEY RESULTS

In vitro, artesunate promoted apoptosis and differentiation in both leukaemia cell lines and patient-derived primary leukaemia cells. Mechanistically, artesunate promoted cell apoptosis by triggering reactive oxygen species (ROS) production and increasing expression of the pro-apoptotic protein Bim. Interestingly, transferrin receptor 1 (TFRC)-mediated regulation of intracellular iron homeostasis also played an essential role in AML cell differentiation induced by artesunate. In vivo, artesunate slowed AML progression and prolonged survival in a mouse leukaemia model. Notably, artesunate displayed no apparent toxicity towards healthy haematopoietic stem cells, bone marrow mononuclear cells or experimental animals.

CONCLUSION AND IMPLICATIONS

Artesunate is a safe agent with significant anti-leukaemia effects in mice and may serve as a promising chemotherapeutic strategy for patients with AML, based on two different mechanisms, targeting the ROS/Bim and the TFRC/Fe²⁺ pathways.

Deregulated calcium signaling in blood cancer: Underlying mechanisms and therapeutic potential

Intracellular calcium signaling regulates diverse physiological and pathological processes. In solid tumors, changes to calcium channels and effectors via mutations or changes in expression affect all cancer hallmarks. Such changes often disrupt transport of calcium ions (Ca2+) in the endoplasmic reticulum (ER) or mitochondria, impacting apoptosis. Evidence rapidly accumulates that this is similar in blood cancer. Principles of intracellular Ca2+ signaling are outlined in the introduction. We describe different Ca2+-toolkit components and summarize the unique relationship between extracellular Ca2+ in the endosteal niche and hematopoietic stem cells. The foundational data on Ca2+ homeostasis in red blood cells is discussed, with the demonstration of changes in red blood cell disorders. This leads to the role of Ca2+ in neoplastic erythropoiesis. Then we expand onto the neoplastic impact of deregulated plasma membrane Ca2+ channels, ER Ca2+ channels, Ca2+ pumps and exchangers, as well as Ca2+ sensor and effector proteins across all types of hematologic neoplasms. This includes an overview of genetic variants in the Ca2+-toolkit encoding genes in lymphoid and myeloid cancers as recorded in publically available cancer databases. The data we compiled demonstrate that multiple Ca2+ homeostatic mechanisms and Ca2+ responsive pathways are altered in hematologic cancers. Some of these alterations may have genetic basis but this requires further investigation. Most changes in the Ca2+-toolkit do not appear to define/associate with specific disease entities but may influence disease grade, prognosis, treatment response, and certain complications. Further elucidation of the underlying mechanisms may lead to novel treatments, with the aim to tailor drugs to different patterns of deregulation. To our knowledge this is the first review of its type in the published literature. We hope that the evidence we compiled increases awareness of the calcium signaling deregulation in hematologic neoplasms and triggers more clinical studies to help advance this field.

Progress on structural modification of Tetrandrine with wide range of pharmacological activities

Tetrandrine (Tet), derived from the traditional Chinese herb Fangji, is a class of natural alkaloids with the structure of bisbenzylisoquinoline, which has a wide range of physiological activities and significant pharmacfological effects. However, studies and clinical applications have revealed a series of drawbacks such as its poor water solubility, low bioavailability, and the fact that it can be toxic to humans. The results of many researchers have confirmed that chemical structural modifications and nanocarrier delivery can address the limited application of Tet and improve its efficacy. In this paper, we summarize the anti-tumor efficacy and mechanism of action, anti-inflammatory efficacy and mechanism of action, and clinical applications of Tet, and describe the progress of Tet based on chemical structure modification and nanocarrier delivery, aiming to explore more diverse structures to improve the pharmacological activity of Tet and provide ideas to meet clinical needs.

Ursolic acid enhances the antitumor effects of sorafenib associated with Mcl-1-related apoptosis and SLC7A11-dependent ferroptosis in human cancer

As a broad-spectrum oral small molecule inhibitor targeting multikinase, sorafenib is currently approved for the clinical treatment of several types of cancer as a single agent. A considerable number of clinical trial results have indicated that combination therapies involving sorafenib have been shown to improve treatment efficacy and may lead to novel therapeutic applications. Ursolic acid (UA), a natural pentacyclic triterpene compound extracted from a great variety of traditional medicinal plants and most fruits and vegetables, exhibits a wide range of therapeutic potential, including against cancer, diabetes, brain disease, liver disease, cardiovascular diseases, and sarcopenia. In the present study, we investigated the antitumor effects of sorafenib in combination with ursolic acid and found that the two agents displayed significant synergistic antitumor activity in in vitro and in vivo tumor xenograft models. Sorafenib/UA induced selective apoptotic death and ferroptosis in various cancer cells by evoking a dramatic accumulation of intracellular lipid reactive oxygen species (ROS). Mechanistically, the combination treatment promoted Mcl-1 degradation, which regulates apoptosis. However, decreasing the protein level of SLC7A11 plays a critical role in sorafenib/UA-induced cell ferroptosis. Therefore, these results suggest that the synergistic antitumor effects of sorafenib combined with ursolic acid may involve the induction of Mcl-1-related apoptosis and SLC7A11-dependent ferroptosis. Our findings may offer a novel effective therapeutic strategy for tumor treatment.

Tetrandrine Inhibits Skeletal Muscle Differentiation by Blocking Autophagic Flux

Tetrandrine is well known to act as a calcium channel blocker. It is a potential candidate for a tumor chemotherapy drug without toxicity. Tetrandrine inhibits cancer cell proliferation and induces cell death through apoptosis and autophagy. As cancer patients usually experience complications with sarcopenia or muscle injury, we thus assessed the effects of tetrandrine on skeletal muscle cells. We report in this study that a low dose of tetrandrine (less than 5 μM) does not affect the proliferation of C2C12 myoblasts, but significantly inhibits myogenic differentiation. Consistently, tetrandrine inhibited muscle regeneration after BaCl₂-induced injury. Mechanistic experiments showed that tetrandrine decreased the p-mTOR level and increased the levels of LC3 and SQSTM1/p62 during differentiation. Ad-mRFP-GFP-LC3B transfection experiments revealed that the lysosomal quenching of GFP signals was suppressed by tetrandrine. Furthermore, the levels of DNM1L/Drp1, PPARGA1 and cytochrome C (Cyto C), as well as caspase 3 activation and ROS production, were decreased following tetrandrine administration, indicating that the mitochondrial network signaling was inhibited. Our results indicate that tetrandrine has dual effects on autophagic flux in myoblasts during differentiation, activation in the early stage and blockade in the late stage. The ultimate blocking of autophagic flux by tetrandrine led to the disruption of mitochondria remodeling and inhibition of myogenic differentiation. The inhibitory effects of tetrandrine on skeletal muscle differentiation may limit its application in advanced cancer patients. Thus, great attention should be paid to the clinical use of tetrandrine for cancer therapy.

Targeting cyclin-dependent kinases 4/6 inhibits survival of megakaryoblasts in acute megakaryoblastic leukaemia

Acute megakaryoblastic leukaemia (AMKL) is characterized by expansion of megakaryoblasts, which are hyper-proliferative cells that fail to undergo differentiation. Insight to the cell-cycle regulation revealed important events in early or late megakaryocytes (MKs) maturation; the cyclin-dependent kinases 4 and 6 (CDK4/6) have been reported to participate in the development of progenitor megakaryocytes, mainly by promoting cell cycle progression and DNA polyploidization. However, it remains unclear whether the continuous proliferation, but not differentiation, of megakaryoblasts is related to an aberrant regulation of CDK4/6 in AMKL. Here, we found that CDK4/6 were up regulated in patients with AMKL, and persistently maintained at a high level during the differentiation of abnormal megakaryocytes in vitro, according to a database and western blot. Additionally, AMKL cells were exceptionally reliant on the cell cycle regulators CDK4 or 6, as blocking their activity using an inhibitor or short hairpin RNA (shRNA) significantly reduced the proliferation of 6133/MPL megakaryocytes, reduced DNA polyploidy, induced apoptosis, decreased the level of phosphorylated retinoblastoma protein (p-Rb), and activation of caspase 3. Additionally, CDK4/6 inhibitors and shRNA reduced the numbers of leukemia cells in the liver and bone marrow (BM), alleviated hepatosplenomegaly, and prolonged the survival of AMKL-transplanted mice. These results suggested that blocking the activity of CDK4/6 may represent an effective approach to control megakaryoblasts in AMKL.

Autophagy and cancer: Can tetrandrine be a potent anticancer drug in the near future?

Autophagy is an essential catabolic process in mammalian cells to maintain cellular integrity and viability by degrading the old and damaged cell organelles and other contents with the help of lysosomes. Deregulation in autophagy can be one of the major contributors leading to the continuous cell proliferation and development of tumors. Tetrandrine, a bisbenzylisoquinoline alkaloid known to have potent bioactivities such as anticancer, antimicrobial, anti-inflammatory, antidiabetic, antioxidant, immunosuppressive, cardiovascular, and calcium channel blocking effects. The present review evaluated the effectiveness of tetrandrine in targeting key proteins in the autophagy pathway to induce anticancer effect based on the available literature. An attempt is also made to understand the influence of tetrandrine in regulating autophagy by mTOR dependant and mTOR-independent pathways. In addition, the review also highlights the limitations involved and future perspectives in developing tetrandrine as a chemotherapeutic drug to treat cancer.

Tetrandrine Ameliorates Traumatic Brain Injury by Regulating Autophagy to Reduce Ferroptosis

Traumatic brain injury (TBI) is the leading cause of death and disability in trauma patients. However, the effects and mechanism of autophagy after TBI remain unclear. This study aimed to investigate whether tetrandrine could ameliorate TBI through autophagy to reduce ferroptosis. A mice model for TBI was implemented. Behavioral and histomorphological experiments were performed to evaluate outcomes of the mice. The ferroptosis levels was detected by Perls staining. Enzyme-linked immunosorbent assay (ELISA) was applied to detect malondialdehyde (MDA), glutathione (GSH), and glutathione peroxidase 4 (GPX4) levels in the brain tissue. Western blot test was performed to detect Beclin 1, light chain 3 (LC3) II/I, p62, GPX4, SCL7A11, and ferritin heavy chain 1 (FTH1) levels, and the expression of LC3B, Beclin 1, GPX4, and FTH1 in the brain tissue was detected by immunofluorescence (IF). The behavioral and histomorphological results demonstrated that tetrandrine improved the neurological function and cerebral edema on days 1, 3, and 7 after TBI. The ELISA results suggested that tetrandrine reduced the MDA concentration and increased GSH concentration on days 1, 3, and 7 after TBI. IF staining and Perls staining reflected that tetrandrine promoted autophagy and inhibited ferroptosis on days 1, 3, and 7 after TBI, respectively. Tetrandrine further improved the neurological function, cerebral edema, autophagy, and ferroptosis on days 1, 3, and 7 after TBI after adding the autophagy inducer rapamycin. The effect of TET in alleviating TBI increased with the increase of time and dose. Tetrandrine ameliorated TBI by regulating autophagy to reduce ferroptosis, providing a new therapeutic strategy for TBI.

Targeting the two-pore channel 2 in cancer progression and metastasis

The importance of Ca²⁺ signaling, and particularly Ca²⁺ channels, in key events of cancer cell function such as proliferation, metastasis, autophagy and angiogenesis, has recently begun to be appreciated. Of particular note are two-pore channels (TPCs), a group of recently identified Ca²⁺-channels, located within the endolysosomal system. TPC2 has recently emerged as an intracellular ion channel of significant pathophysiological relevance, specifically in cancer, and interest in its role as an anti-cancer drug target has begun to be explored. Herein, an overview of the cancer-related functions of TPC2 and a discussion of its potential as a target for therapeutic intervention, including a summary of clinical trials examining the TPC2 inhibitors, naringenin, tetrandrine, and verapamil for the treatment of various cancers is provided.

Tetrandrine Modulates Rheb-mTOR Signaling-Mediated Selective Autophagy and Protects Pulmonary Fibrosis

Idiopathic pulmonary fibrosis is a progressive fatal disease characterized by interstitial remodeling, with high lethality and a lack of effective medical therapies. Tetrandrine has been proposed to present anti-fibrotic effects, but the efficacy and mechanisms have not been systematically evaluated. We sought to study the potential therapeutic effects and mechanisms of tetrandrine against lung fibrosis. The anti-fibrotic effects of tetrandrine were evaluated in bleomycin-induced mouse models and TGF-β1-stimulated murine lung fibroblasts. We performed Chromatin Immunoprecipitation (ChIP), Immunoprecipitation (IP), and mRFP-GFP-MAP1LC3B adenovirus construct to investigate the novel mechanisms of tetrandrine-induced autophagy. Tetrandrine decreased TGF-β1-induced expression of α-smooth muscle actin, fibronectin, vimentin, and type 1 collagen and proliferation in fibroblasts. Tetrandrine restored TGF-β1-induced impaired autophagy flux, accompanied by enhanced interaction of SQSTM1 and MAP1LC3-Ⅱ. ChIP studies revealed that tetrandrine induced autophagy via increasing binding of NRF2 and SQSTM1 promoter. Furthermore, tetrandrine inhibited TGF-β1-induced phosphorylation of mTOR by reducing activation of Rheb. In vivo tetrandrine suppressed the bleomycin-induced expression of fibrotic markers and improved pulmonary function. Our data suggest that protective effect of tetrandrine against lung fibrosis might be through promoting Rheb-mTOR and NRF2-SQSTM1 mediated autophagy. Tetrandrine may thus be potentially employed as a novel therapeutic medicine against IPF.

Small peptide targeting ANP32A as a novel strategy for acute myeloid leukemia therapy

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H3BP targeted ANP32A against AML by competitively disrupting ANP32A and H3 interaction and decreasing H3 acetylation and the expression of lipid metabolism genes.

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Expressed H3BP-GFP and synthetic TAT-H3BP peptide impaired H3 acetylation on multiple locus of target genes that reduced proliferation and caused apoptosis of leukemia cells in vitro.

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TAT-H3BP exhibits potent efficacy against leukemia in vivo: Intra-tumor injection of TAT-H3BP peptide prominently diminished the volume of subcutaneous tumors in nude mice; AMKL mice engrafted with TAT-H3BP-pretreated 6133/MPL W515L cells displayed dramatically moderated disease burden and prolonged survival time.

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TAT-H3BP peptide possess a therapeutic potential in patients with AML for micromole concentration of TAT-H3BP peptide efficiently inhibited the proliferation and CFU of human primary leukemia cells from AML patients.

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High ANP32A levels in human primary AML cells correlate with the intervention effect of TAT-H3BP peptide.

Clinic therapy of acute myeloid leukemia (AML) remains unsatisfactory that urges for development of novel strategies. Recent studies identified ANP32A as a novel biomarker of unfavorable outcome of leukemia, which promoted leukemogenesis by increasing H3 acetylation and the expression of lipid metabolism genes. It is of great significance to investigate whether targeting ANP32A is a novel strategy for leukemia therapy. To target ANP32A, we identified a peptide that competed with ANP32A to bind to histone 3 (termed as H3-binding peptide, H3BP). Disrupting ANP32A and H3 interaction by the overexpression of H3BP-GFP fusion protein mimicked the effect of ANP32A knockdown, impaired H3 acetylation on multiple locus of target genes, reduced proliferation, and caused apoptosis in leukemia cells. Furthermore, a synthesized membrane-penetrating peptide TAT-H3BP effectively entered into leukemia cells and phenocopied such effect. In vivo, TAT-H3BP showed potent efficacy against leukemia: Intra-tumor injection of TAT-H3BP significantly reduced the volume of subcutaneous tumors in nude mice and recipient mice engrafted with TAT-H3BP-pretreated 6133/MPL W515L cells exhibited ameliorated leukemia burden and prolonged survival. Noticeably, TAT-H3BP efficiently suppressed proliferation and colony-forming unit of human primary AML cells without affecting normal cord blood cells. Our findings demonstrate that intervening the physical interaction of ANP32A with H3 impairs the oncogenicity of ANP32A and may be a promising therapeutic strategy against AML.

Oxidative stress in leukemia and antioxidant treatment

Oxidative stress is caused by the imbalance between the generation of free radicals/reactive oxygen species (ROS) and the antioxidant defense systems, which can activate various transcription factors and affect their transcriptional pathways. Oxidative stress plays an important role in the occurrence and development of leukemia and is closely related to the treatment and prognosis of leukemia. The standard chemotherapy strategies for the pre-treatment of leukemia have many drawbacks. Hence, the usage of antioxidants and oxidants in the treatment of leukemia is being explored and has been preliminarily applied. This article reviews the research progress of oxidative stress and leukemia. In addition, the application of antioxidants treatment in leukemia has been summarized.

Tetrandrine: a review of its anticancer potentials, clinical settings, pharmacokinetics and drug delivery systems

OBJECTIVES

Tetrandrine, a natural bisbenzylisoquinoline alkaloid, possesses promising anticancer activities on diverse tumours. This review provides systematically organized information on cancers of tetrandrine in vivo and in vitro, discuss the related molecular mechanisms and put forward some new insights for the future investigations.

KEY FINDINGS

Anticancer activities of tetrandrine have been reported comprehensively, including lung cancer, colon cancer, bladder cancer, prostate cancer, ovarian cancer, gastric cancer, breast cancer, pancreatic cancer, cervical cancer and liver cancer. The potential molecular mechanisms corresponding to the anticancer activities of tetrandrine might be related to induce cancer cell apoptosis, autophagy and cell cycle arrest, inhibit cell proliferation, migration and invasion, ameliorate metastasis and suppress tumour cell growth. Pharmaceutical applications of tetrandrine combined with nanoparticle delivery system including liposomes, microspheres and nanoparticles with better therapeutic efficiency have been designed and applied encapsulate tetrandrine to enhance its stability and efficacy in cancer treatment.

SUMMARY

Tetrandrine was proven to have definite antitumour activities. However, the safety, bioavailability and pharmacokinetic parameter studies on tetrandrine are very limited in animal models, especially in clinical settings. Our present review on anticancer potentials of tetrandrine would be necessary and highly beneficial for providing guidelines and directions for further research of tetrandrine.

Design, Synthesis of Novel Tetrandrine-14-l-Amino Acid and Tetrandrine-14-l-Amino Acid-Urea Derivatives as Potential Anti-Cancer Agents

Tetrandrine, a dibenzyltetrahydroisoquinoline alkaloid isolated from the root of the traditional Chinese medicinal plant Stephania tetrandra S. Moore, a member of the Menispermaceae, showed anti-cancer activity by inhibiting cell proliferation, preventing cell cycle progress and induction of cell death and autophagy. In this study, twelve tetrandrine-l-amino acid derivatives and twelve tetrandrine-14-l-amino acid-urea derivatives were designed and synthesized, using C14-aminotetrandrine as raw material. Then the preliminary in vitro anti-cancer activities of these derivatives against human breast cancer cell line MDA-MB-231, human leukemia cell lines HEL and K562 were evaluated. The in vitro cytotoxicity results showed that these derivatives exhibited potent inhibitory effects on cancer cell growth, and the primary structure-activity relationships were evaluated. Notably, compound 3f exhibited satisfactory anticancer activity against all three cancer cell lines, especially the HEL cell line, with the IC₅₀ value of 0.23 µM. Further research showed that 3f could induce G1/S cycle arrest and apoptosis in a dose- and time- dependent manner on the leukemia cell line HEL. The results suggested that 3f may be used as a potential anti-cancer agent for human leukemia.

Tetrandrine Prevents Bone Loss in Ovariectomized Mice by Inhibiting RANKL-Induced Osteoclastogenesis

Postmenopausal osteoporosis (PMOP) is a metabolic bone disease characterized by decreased bone density and strength due to the imbalance between osteogenesis and osteoclastogenesis. Postmenopausal estrogen withdrawal increases proinflammatory cytokines and increases the serum level of Receptor activator of NF-kB ligand (RANKL)/Osteoprotegerin (OPG), which then leads to the overactivation of osteoclastogenesis. Tetrandrine, a bis-benzylisoquinoline alkaloid, has been widely used in the treatment of rheumatoid arthritis clinically in China. Here, we demonstrate that tetrandrine significantly prevented ovariectomy-induced bone loss and inhibited RANKL-induced osteoclastogenesis. In vivo, we found that intraperitoneal injection of tetrandrine (30 mg/kg) every other day markedly reduced bone loss in ovariectomized mice and the serum levels of TRAcp5b, TNF-a, IL-6, CTX-I, and RANKL/OPG were significantly decreased. In vitro, we found that tetrandrine significantly inhibited osteoclast differentiation in bone marrow monocytes (BMMs) and RAW264.7 cells according to the results of osteoclastogenesis-related gene expression, tartrate-resistant acid phosphatase (TRAP) staining and actin-ring formation as well as bone resorption assay. Mechanistically, tetrandrine inhibited RANKL-induced osteoclastogenesis by suppressing NF-kB, Ca2⁺, PI3K/AKT, and MAPKs signaling pathways. Taken together, our findings suggest that tetrandrine suppresses osteoclastogenesis through modulation of multiple pathways and has potential value as a therapeutic agent for PMOP, especially for those suffering from RA and PMOP at the same time.

A critical review: traditional uses, phytochemistry, pharmacology and toxicology of Stephania tetrandra S. Moore (Fen Fang Ji)

ABSTRACT

Stephania tetrandra S. Moore (S. tetrandra) is distributed widely in tropical and subtropical regions of Asia and Africa. The root of this plant is known in Chinese as "Fen Fang Ji". It is commonly used in traditional Chinese medicine to treat arthralgia caused by rheumatism, wet beriberi, dysuria, eczema and inflamed sores. Although promising reports have been published on the various chemical constituents and activities of S. tetrandra, no review comprehensively summarizes its traditional uses, phytochemistry, pharmacology and toxicology. Therefore, the review aims to provide a critical and comprehensive evaluation of the traditional use, phytochemistry, pharmacological properties, pharmacokinetics and toxicology of S. tetrandra in China, and meaningful guidelines for future investigations.

Repurposing of plant alkaloids for cancer therapy: Pharmacology and toxicology

Drug repurposing (or repositioning) is an emerging concept to use old drugs for new treatment indications. Phytochemicals isolated from medicinal plants have been largely neglected in this context, although their pharmacological activities have been well investigated in the past, and they may have considerable potentials for repositioning. A grand number of plant alkaloids inhibit syngeneic or xenograft tumor growth in vivo. Molecular modes of action in cancer cells include induction of cell cycle arrest, intrinsic and extrinsic apoptosis, autophagy, inhibition of angiogenesis and glycolysis, stress and anti-inflammatory responses, regulation of immune functions, cellular differentiation, and inhibition of invasion and metastasis. Numerous underlying signaling processes are affected by plant alkaloids. Furthermore, plant alkaloids suppress carcinogenesis, indicating chemopreventive properties. Some plant alkaloids reveal toxicities such as hepato-, nephro- or genotoxicity, which disqualifies them for repositioning purposes. Others even protect from hepatotoxicity or cardiotoxicity of xenobiotics and established anticancer drugs. The present survey of the published literature clearly demonstrates that plant alkaloids have the potential for repositioning in cancer therapy. Exploitation of the chemical diversity of natural alkaloids may enrich the candidate pool of compounds for cancer chemotherapy and -prevention. Their further preclinical and clinical development should follow the same stringent rules as for any other synthetic drug as well. Prospective randomized, placebo-controlled clinical phase I and II trials should be initiated to unravel the full potential of plant alkaloids for drug repositioning.

Targeting Reactive Oxygen Species in Cancer via Chinese Herbal Medicine

Recently, reactive oxygen species (ROS), a class of highly bioactive molecules, have been extensively studied in cancers. Cancer cells typically exhibit higher levels of basal ROS than normal cells, primarily due to their increased metabolism, oncogene activation, and mitochondrial dysfunction. This moderate increase in ROS levels facilitates cancer initiation, development, and progression; however, excessive ROS concentrations can lead to various types of cell death. Therefore, therapeutic strategies that either increase intracellular ROS to toxic levels or, conversely, decrease the levels of ROS may be effective in treating cancers via ROS regulation. Chinese herbal medicine (CHM) is a major type of natural medicine and has greatly contributed to human health. CHMs have been increasingly used for adjuvant clinical treatment of tumors. Although their mechanism of action is unclear, CHMs can execute a variety of anticancer effects by regulating intracellular ROS. In this review, we summarize the dual roles of ROS in cancers, present a comprehensive analysis of and update the role of CHM—especially its active compounds and ingredients—in the prevention and treatment of cancers via ROS regulation and emphasize precautions and strategies for the use of CHM in future research and clinical trials.

Molecular features, prognosis, and novel treatment options for pediatric acute megakaryoblastic leukemia

INTRODUCTION

Acute megakaryoblastic leukemia (AMegL) is a rare hematological neoplasm most often diagnosed in children and is commonly associated with Down's syndrome (DS). Although AMegLs are specifically characterized and typically diagnosed by megakaryoblastic expansion, recent advancements in molecular analysis have highlighted the heterogeneity of this disease, with specific cytogenic and genetic alterations characterizing different disease subtypes. Areas covered: This review will focus on describing recurrent molecular variations in both DS and non-DS pediatric AMegL, their role in promoting leukemogenesis, their association with different clinical aspects and prognosis, and finally, their influence on future treatment strategies with a number of specific drugs beyond conventional chemotherapy already under development. Expert opinion: Deep understanding of the genetic and molecular landscape of AMegL will lead to better and more precise disease classification in terms of diagnosis, prognosis, and possible targeted therapies. Development of new therapeutic approaches based on these molecular characteristics will hopefully improve AMegL patient outcomes.

Combination therapy with protein kinase inhibitor H89 and Tetrandrine elicits enhanced synergistic antitumor efficacy

BACKGROUND

Tetrandrine, a bisbenzylisoquinoline alkaloid that was isolated from the medicinal plant Stephania tetrandrine S. Moore, was recently identified as a novel chemotherapy drug. Tetrandrine exhibited a potential antitumor effect on multiple types of cancer. Notably, an enhanced therapeutic efficacy was identified when tetrandrine was combined with a molecularly targeted agent. H89 is a potent inhibitor of protein kinase A and is an isoquinoline sulfonamide.

METHODS

The effects of H89 combined with tetrandrine were investigated in vitro with respect to cell viability, apoptosis and autophagy, and synergy was assessed by calculation of the combination index. The mechanism was examined by western blot, flow cytometry and fluorescence microscopy. This combination was also evaluated in a mouse xenograft model; tumor growth and tumor lysates were analyzed, and a TUNEL assay was performed.

RESULTS

Combined treatment with H89 and tetrandrine exerts a mostly synergistic anti-tumor effect on human cancer cells in vitro and in vivo while sparing normal cells. Mechanistically, the combined therapy significantly induced cancer cell apoptosis and autophagy, which were mediated by ROS regulated PKA and ERK signaling. Moreover, Mcl-1 and c-Myc were shown to play a critical role in H89/tetrandrine combined treatment. Mcl-1 ectopic expression significantly diminished H89/tetrandrine sensitivity and amplified c-Myc sensitized cancer cells in the combined treatment.

CONCLUSION

Our findings demonstrate that the combination of tetrandrine and H89 exhibits an enhanced therapeutic effect and may become a promising therapeutic strategy for cancer patients. They also indicate a significant clinical application of tetrandrine in the treatment of human cancer. Moreover, the combination of H89/tetrandrine provides new selectively targeted therapeutic strategies for patients with c-Myc amplification.

Autophagy as a pharmacological target in hematopoiesis and hematological disorders

Autophagy is involved in many cellular processes, including cell homeostasis, cell death/survival balance and differentiation. Autophagy is essential for hematopoietic stem cell survival, quiescence, activation and differentiation. The deregulation of this process is associated with numerous hematological disorders and pathologies, including cancers. Thus, the use of autophagy modulators to induce or inhibit autophagy emerges as a potential therapeutic approach for treating these diseases and could be particularly interesting for differentiation therapy of leukemia cells. This review presents therapeutic strategies and pharmacological agents in the context of hematological disorders. The pros and cons of autophagy modulators in therapy will also be discussed.

Design, Synthesis and Anticancer Evaluation of Fangchinoline Derivatives

Twenty fangchinoline derivatives were synthesized from the natural product fangchinoline, and their anticancer activities on human breast cancer MDA-MB-231 cell line, human prostate cancer PC3 cell line, human melanoma WM9 cell line and human leukaemia HEL and K562 cell lines were evaluated. The biological result showed that those derivatives exhibited potent activities on inhibiting cancer cell growth, and the structure-activity relationships were investigated. Among them, compound 4g, which was protected by benzoyl group in 7-phenolic position and nitrified in 14-position, showed impressive inhibition on all 5 cancer cell lines, especially WM9 cell line, with an IC50 value of 1.07 µM. Further mechanistic studies demonstrated that compound 4g may induce cancer cell death by apoptotic means. These research results suggested that compound 4g could be a lead for the further development toward an anticancer agent against human melanoma WM9 in the future.

Tetrandrine antagonizes acute megakaryoblastic leukaemia growth by forcing autophagy-mediated differentiation

BACKGROUND AND PURPOSE

The poor prognosis of acute megakaryoblastic leukaemia (AMKL) means there is a need to develop novel therapeutic methods to treat this condition. It was recently shown that inducing megakaryoblasts to undergo terminal differentiation is effective as a treatment for AMKL. This encouraged us to identify a compound that induces megakaryocyte differentiation, which could then act as a potent anti-leukaemia agent.

EXPERIMENTAL APPROACH

The effects of tetrandrine on the expression of CD41 and cell morphology were investigated in AMKL cells. We used CRISPR/Cas9 knockout system to knock out ATG7 and verify the role of autophagy in tetrandrine-induced megakaryocyte differentiation. shNotch1 and CA-Akt were transfected into K562 cells to examine the downstream pathways of ROS signalling and the mechanistic basis of the tetrandrine-induced megakaryocyte differentiation. The anti-leukaemia effects of tetrandrine were analysed both in vitro and in vivo.

KEY RESULTS

A low dose of tetrandrine induced cell cycle arrest and megakaryocyte differentiation in AMKL cells via activation of autophagy. Molecularly, we demonstrated that this effect is mediated by activation of Notch1 and Akt and subsequent accumulation of ROS. In contrast, in normal mouse fetal liver cells, although tetrandrine induced autophagy, it did not affect cell proliferation or promote megakaryocyte differentiation, suggesting a specific effect of tetrandrine in malignant megakaryoblasts. Finally, tetrandrine also showed in vivo efficacy in an AMKL xenograft mouse model.

CONCLUSIONS AND IMPLICATIONS

Modulating autophagy-mediated differentiation may be a novel strategy for treating AMKL, and tetrandrine has the potential to be developed as a differentiation-inducing agent for AMKL chemotherapy.